Many people have a need in their homes, in their businesses, or while pursuing other activities, to keep track of a number of information items that may not be directly related to each other. Some information may be calendar items that demand immediate action; some may need action, but only at a later time; and other items may not require any action at all. Determining priorities is not always easy. Since priorities may change often, it is important to be able to reevaluate and adapt to any change in priorities quickly and efficiency.
In the present modern world much information is stored, processed, and recovered by use of computer technology of one kind or another. But computers, and the electricity to operate them, are not always available. Furthermore, some people prefer an alternative method of record keeping.